public class test {
    public static void main(String[] args) {
        singleLinkedList list = new singleLinkedList();
        list.addFirst(1);
        list.addFirst(2);
        list.addFirst(3);

        list.addLast(4);
        list.addLast(5);
        list.addLast(6);

        list.addIndex(3,3);

        list.remove(6);
        list.removeAllKey(3);
        list.display();
    }
}
